Numerical simulation of electroosmotic flow in hydrophobic microchannels

Electroosmotic flow (EOF) is a promising way for driving and mixing fluids in microfluidics. For the parallel-plate microchannel with the hydrophobic surface, this paper solved the governing equations using the finite element method (FEM), and the effects of microchannel height, electric strength and ionic concentration on EOF were thus investigated. The simulation indicates that the transient characteristics of EOF are similar in hydrophobic and hydrophilic microchannels, the steady time of EOF is proportional to the square of microchannel height, and the scale is microsecond. EOF velocity is proportional to the electric strength and independent of the channel height, and decreases slowly with the ionic concentration, which is lower than that in hydrophilic microchannel due to the presence of slip length in hydrophobic microchannel. The results can provide valuable insights into the optimal design of microchannel surfaces to achieve accurate EOF control in hydrophobic microchannel. Supported by the National Natural Science Foundation of China (Grant No. 50730007)     

A new type counter electrode for dye-sensitized solar cells

A new type counter electrode for dye-sensitized solar cells (DSCs) was proposed which consists of substrate, aluminum film and platinum film. The new type counter electrode can obviously improve the photoelectric conversion efficiency of DSCs from 3.46% to 7.07% under the standard AM1.5 irradiation condition. Advantages and shortcomings of this new type counter electrode in terms of electrical properties, optical properties and anti-corrosive properties were analyzed. As a result, some improvements were proposed. Supported by the Key Foundation for Fundamental Research of Tianjin Municipal Science & Technology Commission in China ( Grant No. 06YFJZJC01700) and the National Basic Research Program of China (“973“ Project) (Grant Nos. 2006CB20260, 2006CB202603)     

论船籍登记及船东的船籍选择

以船舶登记制度为研究对象,通过分析比较的方法,讨论了船东船籍选择的考虑因素,及实务中我国船东船籍外移的原因,提出了控制我国目前船籍外移现象有效的解决方法.     

基于均值平移的自动人脸检测与跟踪算法

针对彩色图像序列的人脸跟踪问题,提出了一种基于均值平移的自动人脸检测与跟踪算法.对每帧图像采用基于肤色和支持向量机的算法检测人脸,可以减少计算量.对于检测到的人脸,判断是否含有新增人脸,有则将新的人脸加入跟踪序列,否则继续跟踪原有人脸序列.然后采用均值平移算法对人脸序列进行跟踪,其计算量小,跟踪稳定可靠,从而实现自动的人脸检测与跟踪.实验结果表明,该算法可以很好地进行人脸的自动检测跟踪.     

具有分布时滞的Liénard型方程周期解的存在性

考察了具有分布时滞的Liénard型方程,利用重合度理论研究其周期解问题,得到了该方程周期解存在的充分条件,结论丰富了现有文献的结果．     

陕西对外贸易与经济增长关系的协整分析

以陕西省作为研究对象,根据陕西省1980—2007年的数据,利用Granger因果关系检验、协整分析和误差修正模型分析陕西省对外贸易和经济增长的关系,结果表明,陕西省对外贸易和经济增长存在长期的协整关系;陕西属于出口导向型经济,出口是经济增长的Granger原因,进口不是经济增长的Granger原因,却是出口增长的Grange原因,由此说明,进口对经济增长有间接的作用。     

跨学科发展与英语专业应用型人才培养的研究

从跨学科发展的角度对地方院校英语专业培养应用型人才的培养目标和课程设置予以研究,试图探索地方院校英语专业改革和发展的方向。     

胆固醇氧化酶高产菌株的诱变选育及产酶条件优化

在对细脚拟青霉、玫烟色拟青霉、粉拟青霉、香菇、平菇、金针菇等胆固醇氧化酶产生菌初筛的基础上．选择以产酶较高的玫烟色拟青霉作为紫外诱变的出发菌株,筛选出一株相对高产突变菌株MFEC006,其酶活达到了0．5483U／mL,比出发菌株提高了154％,经8次传代培养,突变株性质稳定．对MFEC006菌株产酶条件进行优化,得出其最佳产酶条件为：pH为6．5,温度27℃,接种量10％,摇床转速180r／min．     

Novel fixed‐carrier membranes for CO2 separation

A new membrane material having two kinds of CO₂ carriers was obtained. Composite membranes were prepared with the material and support membranes. The facilitated transport of CO₂ through these membranes was performed with pure CH₄ and CO₂ as well as CH₄/CO₂ mixtures containing 50 vol % CO₂. The results show that the membranes possess better CO₂ permeance than that of other fixed carrier membranes reported in the literature. In the measurements with pure gases, at 26°C, 0.013 atm of CO₂ pressure, the membrane with polysulfone support displays a CO₂ permeance of 7.93 × 10^?4 cm³ /cm² s cmHg and CO₂/CH₄ ideal selectivity of 212.1. In the measurements with mixed gases, at 26°C, 0.016 atm of CO₂ partial pressure, the membrane displays a CO₂ permeance of 1.69 × 10^?4 cm³ /cm² s cmHg and CO₂/CH₄ selectivity of 48.1. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2222–2226, 2002     

离心三相分离过程数值模拟研究

悬浮液的沉降过程主要由固相颗粒浓度和凝聚状态等决定,为了定量描述油渣水在离心力场中的分离过程,以含油渣水三相的罐底油为研究对象,提出固-液-液三相离心分离的概念,进行模型分析,采用计算流体力学软件FLUENT对其分离过程进行数值模拟研究,分析了其影响因素。研究表明:数值模拟与实验结果基本一致,利用FLUENT软件模拟三相离心分离过程符合实际状况,能够很好的指导实践。